In the flooring industry, there is a significant need for waterproof flooring that presents the appearance of a wooden floor. In particular, this flooring needs to be not only resistant to moisture, but also economical, easy to install, easy to maintain, and comfortable to walk on.
In the flooring industry, laminate flooring using fiberboard or particle board as the core layer has gained a tremendous market share. Such laminate flooring is manufactured with numerous desirable properties such as reasonable cost, stain resistance, wear resistance, easy maintenance, and fire resistance. In addition, laminate flooring is able to carry many types of printed designs, including wood grain designs.
Natural wood floors, particularly of oak and other hardwoods have been employed as flooring materials for centuries. While not as economical as laminate flooring, the appearance and comfort of wooden flooring is highly desirable. One of the most significant drawbacks to both laminate and wooden flooring is their performance when subjected to sustained exposure to moisture. In the case of wooden floors, moisture will cause swelling and warping of the flooring leading to an uneven surface and even gaps between the planks. In the case of laminate flooring, sustained exposure to moisture will frequently destabilize the integrity of the fiberboard or particle board material causing permanent and irreparable damage to the laminate boards. This leads many flooring installers to avoid the use of laminate flooring in areas that are subject to repeated or sustained moisture such as in the kitchen, bathroom, laundry room and basement areas of a house or in the commercial settings of restaurants and some retail stores.
As a result of the shortcomings of wood and laminate flooring, the choices for flooring in wet areas have traditionally been limited to ceramic tile, stone, and rubber or vinyl flooring. With ceramic tile and stone, the visual choices are limited, the cost of materials and installation is relatively high, and the resulting floors are cold in the absence of subsurface radiant heating and hard to stand on for extended periods of time. Rubber and vinyl floors can be relatively inexpensive, however, because these flooring materials are not rigid, imperfections from the subfloor transfers through the rubber or vinyl and appears on the floor surface which can be aesthetically jarring. In addition, the strength of adhesives used with rubber and vinyl floors can be compromised by moisture that can result in curling damage since the floors lack rigidity.
To address these issues, laminate flooring has been manufactured with improved moisture resistance through the selection of melamine, isocyanate or phenolic binders and through application of waterproofing materials and silicone caulking to seal voids. These steps remain inadequate however, both due to added time of installation and cost of manufacture, and because these waterproofing attempts are not 100% effective. One attempt to produce a suitable laminate plank is described in U.S. Pat. No. 7,763,345, and its related applications, where a thermoplastic material core is created and a print layer and a protective overlay are applied to the top side. The thermoplastic material core is typically a rigid polyvinylchloride compound and the core is extruded with cavities to provide cushioning. Extruded planks have a tendency to cup, however, and even with cavities, the PVC thermoplastic core is not inexpensive.
In modern construction it is also desirable to utilize green or recycled materials to minimize the environmental cost of construction. As a result, it is desirable to maximize the use of recycled or waste materials whenever possible. Therefore, a need exists for improved waterproof engineered flooring and wall covering material.